JPH04244762A - Rotor shaft for rotary electric machine - Google Patents

Abstract

PURPOSE:To easily reduce an increase in a vibration due to a temperature rise by forming a plurality of passages axially on an outer periphery, and regulating the quantity of cooling air flowing in and out through the passages by a regulating plate. CONSTITUTION:In a rotor of a rotary electric machine, cooling air blown inside an inner blade 8 is substantially uniformly blown to vent grooves 2 formed on the outer periphery of the center of a rotor shaft as indicated by an arrow 9, and fed between the outer periphery of a rotor core 3 and a stator though vent holes 3a formed at the core 3 to cool the shaft 1 and the core 3. A regulating plate 10 is inserted to the groove 2 disposed at the upper center. Thus, the ventilation amount of the other side of the rotor bent at one side is regulated by a temperature rise due to energization to correct the bent of the shaft due to the temperature rise. Further, the plate 10 is hit to be fitted at the inner peripheral side in the groove 2, further clamped with a screw in the vicinity of its axial center, and hence there is no fear of loosening it by a centrifugal force.

Description

[Detailed description of the invention]

[Purpose of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rotor shaft of a rotating electric machine.

0002

[Prior Art] In rotating electric machines, when the vibration of the rotor that occurs during operation becomes excessive, the life of the bearings is shortened, damage to the bearings, and instrumentation of the air passages and terminal boxes attached to the stator side is reduced. It can also cause product damage. Then, when this electric motor is used, for example, in a steel rolling mill, a large compressor, or a pump, there is a possibility that the operation of the entire facility must be stopped.

[0003] For this reason, in large electric motors used in such equipment, it has been necessary to adjust the deviation of the center of gravity relative to the axis, which causes excessive vibration of the rotor during operation, at each stage of assembly and testing. This is intended to reduce the unbalance of centrifugal force caused by rotation and reduce vibration associated with it.

On the other hand, as the load increases, the internal temperature of an electric motor increases, and even if the vibration is small under no-load conditions, the rotor expands as the load increases, causing it to bend as shown in FIG. Sometimes the vibration gets louder. FIG. 5 is a graph showing the magnitude and direction of vibration of the rotor of a conventional induction motor measured by the inventor in a no-load state and when the temperature rise is saturated at a rated load.

In the figure, when there is no load and the temperature at the end of the rotor is 18°C, the maximum amplitude is 20 μm in the direction of 198° when one side of the rotor is 0°. The one that was showing 15% when the load was increased to the rated load
After 15 minutes, the phase shift of the vibration changes to 180 degrees and the maximum amplitude decreases to 10 μm, and after another 15 minutes, the phase shift of the vibration changes to 53 degrees and the maximum amplitude is 20 μm, which is the amplitude at no load. It increased to After that, measurements were taken every 20 minutes, but the first 2
When 0 minutes have elapsed, it changes in the direction of 42 degrees and reaches a maximum amplitude of 30 degrees.
After the next 20 minutes, the direction of the vibration phase shift further becomes 37 degrees in the direction of 0 degrees, and the maximum amplitude increases to 40 μm, and when the temperature rise reaches saturation at 60 degrees after the next 20 minutes. The phase shift of the vibration was 35° and the amplitude was 60 μm. For this reason, various measures have been conventionally taken to heat-treat the rotating shaft of a rotating electric machine before finishing to minimize distortion due to temperature rise.

[0006]

[Problem to be Solved by the Invention] However, the rotor core, conductors, etc. are attached to the rotor shaft of the electric motor, and induction motors are assembled through processes such as brazing short-circuit rings. Not only is the heat generation and dissipation of the child core and conductor not completely uniform, but the direction of bending may change depending on the temperature as described above.

[0007] For this reason, there is a method of increasing the cooling effect by increasing the capacity of the inner fan, but this has the drawback of increasing noise. Alternatively, a method of forcibly restraining vibration by increasing the rigidity of the bearing may be adopted, but this method is time-consuming and has little effect. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to obtain a rotor shaft for a rotating electric machine that can easily reduce the increase in vibration due to temperature rise. [Structure of the invention]

[0008]

[Means and Effects for Solving the Problems] The present invention provides a rotor shaft of a rotating electric machine in which a plurality of ventilation passages are formed in the axial direction of the outer periphery, and cooling air is forced into the ventilation passages.
By providing an adjustment plate that adjusts the amount of cooling air ventilated in this ventilation path, the amount of ventilation on the other side of the rotor shaft, which curves to one side due to temperature rise due to energization, can be adjusted, and the curvature of the rotor shaft can be prevented. This is a rotor shaft for rotating electric machines that can easily reduce vibrations caused by an unbalanced center of gravity.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the rotating shaft of a rotating electric machine according to the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal cross-sectional view showing a rotating shaft of a rotating electric machine according to the present invention, and FIG. 2 is an enlarged detailed view of a cross section in a direction orthogonal to the central axis of the rotating shaft 1 of FIG. 1. As shown in FIG.

In FIGS. 1 and 2, in the middle part of the rotor shaft 1, there are 45 ventilation grooves 2 in the axial direction of the outer circumference as shown in FIG.
They are formed at ゜ intervals. On the other hand, a rotor core 3 made of laminated silicon steel plates is inserted into the outer periphery of the rotor shaft 1, and the rotor core 3 has ventilation holes 3a penetrating from the inner periphery to the outer periphery at approximately equal intervals in the axial direction. 3 locations, 4 similar to ventilation groove 2 in Figure 2
These ventilation holes 3a are inserted at approximately the center of each ventilation groove 2, and a plurality of U-shaped grooves 5 are provided in the axial direction on the outer periphery. A conductor 6 is inserted with both ends protruding, and an annular shorting ring 7 is brazed to the inner circumferential surface of both ends of the conductor 6, as shown in a side view (not shown) of FIG. Further, an annular laminated core fixing flange 4 is inserted into both ends of the rotor core 3, and a rectangular plate-shaped adjusting plate 10 is fixed with bolts 10a on the outside thereof as shown in FIG. The shaft center side of this adjusting plate 10 has a ventilation groove 1
It is set to 0. Further, on the outside of this adjustment plate 10, inner fans 8 are inserted into stepped portions of the rotating shaft 1, respectively.

In the rotor of the rotating electric machine constructed in this manner, the cooling air blown inward by the inner fan 8 is directed through each ventilation groove 2 formed on the outer periphery of the center of the rotor shaft, as shown by an arrow 9. It is sprayed almost uniformly onto the rotor core 3 and flows out between the outer periphery of the rotor core 3 and a stator (not shown) through each ventilation hole 3a provided in the rotor core 3, thereby cooling the rotor shaft 1 and the rotor core 3. .

On the other hand, when the rotor shaft 1 bends downward as shown in FIG. 4 due to energization, the adjustment plate 10 is inserted into the ventilation groove 2 located at the upper center as shown in FIG. 5, when the rotor core bends upward under rated load, it is inserted into the ventilation groove 2 located on the lower side.

Also, if there is little bending at the rated load, insert it shallowly, if the bend is large, insert it deeply, and if the bend is even larger, for example, in FIG. Insert it into the ventilation groove 2 at a position of 270° to the right of the
By installing the adjustment plate 10 at a position of 70 degrees slightly shallower, the cooling effect depending on the angle of the outer periphery of the rotating shaft 1 is changed to correct distortion.

FIG. 3 shows the temperature rise when the adjusting plate 10 is inserted into the ventilation groove at a position of 225° with respect to the rotor shaft of an induction motor that has obtained the thermal distortion characteristics as shown in FIG. 5. It is a graph showing the correction effect of time distortion.

In the same figure, the rotor shaft vibrates at a maximum amplitude of about 10 μm when the temperature rise reaches 60° C. and saturates under the rated load, and it is 50 μm before inserting the adjustment plate 10 shown in FIG. This is a decrease of 20% compared to the previous year.

In other words, the rotating shaft that showed a maximum amplitude of 13.5 μm in the 195° direction when no load was applied, showed a maximum amplitude of 20 μm in the same direction 15 minutes after applying the rated load, and then After a minute had passed, the same amplitude was shown in the 205° direction. Furthermore, after the next 15 minutes, the strain decreased significantly and became 6 μm in the 180° direction.
After a minute, it changes to a 90° direction and the same 6 μm, then 20
After one minute, it decreases to 11 μm in the 45° direction, the next 20 minutes, it decreases to 16 μm in the 46° direction, and after the next 20 minutes, the direction reverses and decreases to 13 μm in the 67° direction, and then the next 20 minutes.
Minutes later, it further decreased to 12 μm in the 90° direction, and in the next 20 minutes, when it was saturated at 60°C, it decreased to 10 μm in the 125° direction.
The amplitude became constant at m.

[0017] In addition, during the above test, in Fig. 5 2
The adjustment plate 10 was inserted into the ventilation groove at the 25° position, but the angle was 180°.
Adjustment plate 10 slightly protruding from the ventilation groove at the ° position
By providing this, the amplitude broken line shown in FIG. 3 can be shifted to the right to further reduce the amplitude at the rated load. Therefore, by accumulating thermal characteristic data as shown in Figs. 3 and 5 for each rotating machine by type and rating, the adjustment plate 1
0 installation position and installation depth can be determined.

As a result, in the rotor of the rotating electric machine constructed as described above, it is possible to insert a component for correcting the eccentricity of the center of gravity, for example, by forming a female thread on the outer surface of the rotor laminated core fixing flange 4 and forming a male thread on the outer surface of the rotor laminated core fixing flange 4. As with the case, the adjustment plate 10 has its inner circumferential side folded into the ventilation groove 2 and is further attached with screws closer to the axis, so there is no risk of it loosening due to centrifugal force, and it can be manufactured using sheet metal processing, making it easy to manufacture. It becomes the rotor of a rotating electric machine. In the above embodiment, the bolt holes for fixing the adjustment plate 10 may be oval to facilitate adjustment.

Furthermore, although the above embodiments have been explained using an example of a squirrel-cage induction motor, the present invention can be applied to any rotating machine in which a cooling ventilation air passage is formed in the axial direction between the rotor shaft and the rotor core. be able to.

[0020]

As described above, according to the present invention, in a rotating shaft of a rotating electric machine in which a plurality of ventilation passages are formed in the axial direction of the outer periphery, and cooling air flows in and out of the ventilation passages, cooling air flows inside and out of the ventilation passages. By installing an adjustment plate to adjust the amount of cooling air, the amount of airflow on the other side of the rotor, which curves to one side due to temperature rise due to energization, is adjusted, and the bending of the rotor shaft due to temperature rise is corrected. It is possible to obtain a rotor for a rotating electric machine that can reduce the bending of the shaft and easily reduce the amplitude.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing one embodiment of a rotor shaft of a rotating electric machine according to the present invention.

FIG. 2 is an enlarged cross-sectional view in a direction orthogonal to the axis of the rotor shaft of the rotating electric machine of the present invention.

FIG. 3 is a graph showing the action of the rotor shaft of the rotating electric machine of the present invention.

FIG. 4 is a diagram showing an example of a rotor shaft of a conventional rotating electric machine.

FIG. 5 is a graph showing the action of the rotor shaft of a conventional rotating electric machine.

[Explanation of symbols]

1... Rotor shaft 2... Ventilation groove 3... Rotor core 8...
Inner fan 10...adjustment plate

Claims (1)

[Claims] [Claim 1] In a rotor shaft of a rotating electrical machine in which a plurality of ventilation passages are formed in the axial direction of the outer periphery, and cooling air is forced through the ventilation passages, forced ventilation is forced into the ventilation passages. A rotor shaft for a rotating electric machine, characterized in that an adjustment plate is provided to adjust the volume of the cooling air.